With the construction of an intelligent power grid, the dispatching automation system, power charging system, load monitoring system, fault recording device, microcomputer relay protection device, lightning location system, power station system, gate charging system, communication network and the like have higher requirements for clock synchronization. A safe, stable and accurate clock synchronization system has been a necessary form of infrastructure for supporting the safe operation of an intelligent power grid. In the operation of a power system, because the operation states of the power grid change all the time, the power grid dispatching adopts hierarchical multilevel management, and with the dispatching center far away from the site, the time of all the electrical automation apparatuses and microcomputer protection devices in the power plant or power station must be consistent, which is of significance for the operation and accident analysis (in particular, complex accident analysis) of the power grid.
The existing common reference clock signal is acquired the manner where a Beidou signal receiving module and a GPS signal receiving module acquire output signals from a Beidou signal source and a GPS signal source. The Beidou signal is generally taken as the reference clock signal and the reference clock signal is sent to all the synchronization signal receiving apparatuses by a Beidou signal output module. When the Beidou signal source fails, an alarming and blocking module is driven to work by a synchronization signal comparison module. The alarming and blocking module sends an alarm signal to a background monitoring system while sending a blocking signal to the Beidou signal output module, and then the synchronization signal comparison module is automatically switched to the output signal of the GPS signal source before the GPS signal output module sends the reference clock signal to all the synchronization signal receiving apparatuses. If the Beidou signal source and the GPS signal source fail at the same time, the synchronization signal comparison module drives the alarming and blocking module to work, and the alarming and blocking module sends an alarm signal to the background monitoring system while sending a blocking signal to the Beidou signal output module and the GPS signal output module. In general, the switching mode of the abovementioned reference clock signal can normally work. However, in actual use, once the Beidou signal source fails, the synchronization signal comparison module is not automatically switched to the GPS signal source, and meanwhile the alarming and blocking module is not driven to work. Therefore, the occurrence of a reference clock signal fault causes a clock information fault in the whole station and leads to serious consequences.